Semiconductor package and process for fabricating same

ABSTRACT

A package carrier includes: (a) a dielectric layer defining a plurality of openings; (b) patterned electrically conductive layer, embedded in the dielectric layer and disposed adjacent to a first surface of the dielectric layer; a plurality of electrically conductive posts, disposed in respective ones of the openings, wherein the openings extend between a second surface of the dielectric layer to the patterned electrically conductive layer, the electrically conductive posts a connected to the patterned electrically conductive layer, and an end of each of the electrically conductive posts has a curved profile and is faced away from the patterned electrically conductive layer; and (d) a patterned solder resist layer, disposed adjacent to the first surface of the dielectric layer and exposing portions of the patterned electrically conductive layer corresponding to contact pads. A semiconductor package includes the package carrier, a chip, and an encapsulant covering the chip and the package carrier.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/251,396, filed on Oct. 14, 2009, U.S. Provisional Application No. 61/294,519, filed on Jan. 13, 2010, and Taiwan Application No. 99107472, filed on Mar. 15, 2010, the disclosures of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to a semiconductor package. More particularly, the present invention relates to a package carrier, a package structure, and a process for fabricating a package carrier and a package structure.

BACKGROUND

A chip package serves to protect a bare chip, reduce a density of chip contacts, and provide a good heat dissipation effect for the chip. A common packaging process is to install the chip onto a package carrier, and contacts of the chip are electrically connected to the package carrier. Therefore, distribution of the contacts of the chip can be rearranged through the package carrier to cope with a contact distribution of a next stage external device.

As light weight, compactness, and high efficiency have become typical requirements of consumer electronic and communication products, chip packages should provide superior electrical properties, small overall volume, and a large number of I/O ports. Package carriers used in these chip packages often have multiple metal layers that can be electrically connected through interconnections. As the size of chip packages decreases, these interconnections can become smaller and more closely spaced, which can increase the cost and complexity of packaging processes.

It is against this background that a need arose to develop the package carriers, the package structures, and processes described herein.

SUMMARY

Embodiments of the present invention provide a semiconductor package for packaging a chip. Embodiments of the present invention also provide a process for fabricating the aforementioned semiconductor package.

In one embodiment, a semiconductor package includes: (1) a package carrier, including: a dielectric layer having a plurality of openings; a conductive layer disposed adjacent to a first surface of the dielectric layer; and a plurality of conductive posts disposed in respective ones of the openings, wherein each conductive post is connected to the conductive layer and extends away from the conductive layer without protruding from the respective opening; and (2) a chip attached to the package carrier and connected to the conductive layer.

In another embodiment, a semiconductor package includes: (1) a substrate, including: a dielectric layer having a plurality of openings; a conductive layer disposed adjacent to the dielectric layer; and a plurality of conductive vias disposed in respective ones of the openings; (2) a chip attached to the substrate and connected to the conductive layer; and (3) a plurality of conductive bumps disposed adjacent to respective ones of the conductive vias, wherein a first end of each conductive via is connected to the conductive layer and a second end of the conductive via is connected to the respective conductive bump such that the second end of the conductive via does not protrude from the respective opening.

In a further embodiment, a process of fabricating a semiconductor package includes: (1) providing a conductive layer and a plurality of conductive posts disposed adjacent to the conductive layer; (2) disposing a dielectric layer having a plurality of openings on the conductive layer, wherein the openings are coincident with the conductive posts; and (3) patterning the conductive layer.

As to the above, certain embodiments of the present invention first form a plurality of electrically conductive posts connected to an electrically conductive layer (or a patterned electrically conductive layer) and then form a dielectric layer on the conductive layer (or the patterned conductive layer), wherein the dielectric layer exposes a portion of each of the conductive posts. A semiconductor package described herein has the advantages of reduced package size while coping with a particular circuit layout, and controlling the cost and complexity of packaging processes.

Other aspects and embodiments of the invention are also contemplated. The foregoing summary and the following detailed description are not meant to restrict the invention to any particular embodiment but are merely meant to describe some embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of some embodiments of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings. In the drawings, like reference numbers denote like elements, unless the context clearly dictates otherwise.

FIG. 1A is a cross-sectional view of a semiconductor package according to an embodiment of the present invention.

FIG. 1B to FIG. 1H are cross-sectional views of packages according to various embodiments of the present invention.

FIG. 2A is a cross-sectional view of a package according to another embodiment of the present invention.

FIG. 2B to FIG. 2D are cross-sectional views of packages according to various embodiments of the present invention.

FIG. 3A to FIG. 3R illustrate a process of fabricating a package carrier according to an embodiment of the present invention.

FIG. 4A to FIG. 4Q illustrate a process of fabricating a package carrier according to another embodiment of the present invention.

FIG. 5A to FIG. 5M illustrate a process of fabricating a package carrier according to another embodiment of the present invention.

FIG. 6A to FIG. 6M illustrate a process of fabricating a package carrier according to another embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 1A is a cross-sectional view of a semiconductor package 10 a according to an embodiment of the present invention. Referring to FIG. 1A, in the present embodiment, the package 10 a includes a package carrier 100 a (or other substrate), a set of solder balls 102 (or other electrically conductive bumps), a chip 104 (or other active or passive semiconductor device), a set of conductive wires 106, and an encapsulant 108.

Specifically, the package carrier 100 a includes a dielectric layer 110, a patterned electrically conductive layer 120, a set of electrically conductive vias, and a patterned solder resist layer 140 a. In the illustrated embodiment, the conductive vias correspond to electrically conductive posts 130 a, although pillars and other hollow or solid structures can be used. The dielectric layer 110 includes a first surface 112 and a second surface 114 faced away from the first surface 112, and defines a set of openings 116. A material of the dielectric layer 110 can include a resin, such as Ammonium Bifluoride, Ajinomoto build-up film (ABF), Bismaleimide Triazine (BT), Polyimide (PI), liquid crystal polymer (LCP), epoxy resin, or a combination thereof. These resin materials can be mixed with glass fibers, such as in the form of a fiber pad or other types of fibers to strengthen the dielectric layer 110.

The patterned conductive layer 120 is embedded in the dielectric layer 110 and is disposed adjacent to the first surface 112 of the dielectric layer 110. In other words, the patterned conductive layer 120 can be taken as an embedded circuit, and an exposed surface (e.g., a top surface) of the patterned conductive layer 120 is aligned (e.g., substantially aligned) with the first surface 112 of the dielectric layer 110. The patterned conductive layer 120 can include a metal, a metal alloy, or other electrically conductive material. The conductive posts 130 a are respectively disposed in the openings 116, wherein the openings 116 extend from the second surface 114 of the dielectric layer 110 to the patterned conductive layer 120, and the conductive posts 130 a are connected to the patterned conductive layer 120. The conductive posts 130 a can include a metal (e.g., copper), a metal alloy, or other electrically conductive material. In the present embodiment, a height (or other characteristic vertical extent) of each of the conductive posts 130 a is less than a depth (or other characteristic vertical extent) of the corresponding opening 116, such that the conductive posts 130 a do not protrude from the corresponding openings 116. The patterned solder resist layer 140 a is disposed adjacent to the first surface 112 of the dielectric layer 110 and exposes a portion of the patterned conductive layer 120. The exposed portion of the patterned conductive layer 120 can be taken as a set of contact pads.

The solder balls 102 are disposed adjacent to the second surface 114 of the dielectric layer 110 and are located adjacent to their respective conductive posts 130 a. In the present embodiment, since the height of each of the conductive posts 130 a is less than the depth of the corresponding opening 116, a portion (e.g., a top portion) of each of the solder balls 102 is located in the corresponding opening 116.

The chip 104 is mounted adjacent to the package carrier 100 a and located adjacent to the first surface 112 of the dielectric layer 110. In the present embodiment, the package 10 a further includes an adhesive layer 109 a, wherein the adhesive layer 109 a is disposed between the chip 104 and the patterned solder resist layer 140 a to bond the chip 104 to the package carrier 100 a.

The chip 104 is electrically connected to the portion of the patterned conductive layer 120 exposed by the patterned solder resist layer 140 a through the conductive wires 106. The encapsulant 108 covers the chip 104, the conductive wires 106, and a portion of the package carrier 100 a.

By forming connections to the patterned conductive layer 120 (i.e., the embedded circuit) through the conductive posts 130 a, the package 10 a of the present embodiment has the advantages of reduced package size while coping with a particular circuit layout (e.g., the layout of the patterned conductive layer 120), and controlling the cost and complexity of packaging processes. In addition, by forming the conductive posts 130 a within the dielectric layer 110, the stress imparted by external forces, such as attributable to mechanical shock, is compensated for, and the reliability of the package 10 a is improved.

An overall thickness of the package carrier 100 a can be in the range of about 40 μm to about 150 μm, and can also be in one of the ranges of about 40 μm to about 60 μm, about 60 μm to about 80 μm, about 80 μm to about 100 μm, about 80 μm to about 120 μm, and about 40 μm to about 130 μm, although the thickness of the package carrier 100 a is not constrained to any of these ranges. At the same time, the package carrier 100 a can also be sufficiently strong and rigid so that warpage is sufficiently small to meet practical application requirements. In some embodiments, the tensile modulus or Young's modulus of the package carrier 100 a (or a portion thereof, such as the dielectric layer 110) can be in the range of about 10 GPa to about 40 GPa, such as from about 15 GPa to about 40 GPa, from about 20 GPa to about 40 GPa, or from about 30 GPa to about 40 GPa.

FIG. 1B is a cross-sectional view of a package 10 b according to another embodiment of the present invention. Referring to both FIG. 1A and FIG. 1B, the package 10 b of FIG. 1B is similar to the package 10 a of FIG. 1A. At least one difference is that an adhesive layer 109 b of the package 10 b of FIG. 1B is disposed between the chip 104 and a portion of the patterned conductive layer 120 exposed by a patterned solder resist layer 140 b of a package carrier 100 b.

FIG. 1C is a cross-sectional view of a package 10 c according to another embodiment of the present invention. Referring to both FIG. 1A and FIG. 1C, in the present embodiment, the package 10 c of FIG. 1C is similar to the package 10 a of FIG. 1A. At least one difference is that a height of each conductive post 130 b of a package carrier 100 c of FIG. 1C is substantially equal to a depth of the corresponding opening 116. In other words, an end (e.g., a lower end) of each conductive post 130 b is aligned (e.g., substantially aligned or coplanar) with the second surface 114 of the dielectric layer 110, and the solder balls 102 are disposed adjacent to their respective conductive posts 130 b, with little or no portions of the solder balls 102 disposed in the openings 116.

FIG. 1D is a cross-sectional view of a package 10 d according to another embodiment of the present invention. Referring to both FIG. 1A and FIG. 1D, the package 10 d of FIG. 1D is similar to the package 10 a of FIG. 1A. At least one difference is that the adhesive layer 109 b of the package 10 d of FIG. 1D is disposed between the chip 104 and a portion of the patterned conductive layer 120 exposed by the patterned solder resist layer 140 b of a package carrier 100 d. In addition, the height of each conductive post 130 b of the package carrier 100 d is substantially equal to the depth of the corresponding opening 116. In other words, an end (e.g., a lower end) of each conductive post 130 b is aligned (e.g., substantially aligned or coplanar) with the second surface 114 of the dielectric layer 110, and the solder balls 102 are disposed adjacent to their respective conductive posts 130 b, with little or no portions of the solder balls 102 disposed in the openings 116.

FIG. 1E is a cross-sectional view of a package 10 e according to another embodiment of the present invention. Referring to both FIG. 1A and FIG. 1E, the package 10 e of FIG. 1E is similar to the package 10 a of FIG. 1A. At least one difference is that the solder balls 102 of the package 10 e include a set of first solder balls 102 a and a second solder ball 102 b. An orthographic projection of the second solder ball 102 b on the first surface 112 of the dielectric layer 110 is overlapped with an orthographic projection of the chip 104 on the first surface 112 of the dielectric layer 110. In other words, a lateral periphery of the second solder ball 102 b overlaps to at least some degree with a lateral periphery of the chip 104, when viewed from the top or the bottom of the package 10 e. Also, a size (e.g., a characteristic lateral extent) of each of the first solder balls 102 a is smaller than a size of the second solder ball 102 b, and a size (e.g., a characteristic lateral extent) of a conductive post 130 a associated with each of the first solder balls 102 a is smaller than a size of a conductive post 130 a associated with the second solder ball 102 b.

FIG. 1F is a cross-sectional view of a package 10 f according to another embodiment of the present invention. Referring to both FIG. 1A and FIG. 1F, the package 10 f of FIG. 1F is similar to the package 10 a of FIG. 1A. At least one difference is that the adhesive layer 109 b of the package 10 f of FIG. 1F is disposed between the chip 104 and a portion of the patterned conductive layer 120 exposed by the patterned solder resist layer 140 b. In addition, the solder balls 102 of the package 10 f include the first solder balls 102 a and the second solder ball 102 b, similar to that of the package 10 e of FIG. 1E.

FIG. 1G is a cross-sectional view of a package 10 g according to another embodiment of the present invention. Referring to both FIG. 1A and FIG. 1G, the package 10 g of FIG. 1G is similar to the package 10 a of FIG. 1A. At least one difference is that the solder balls 102 of the package 10 g include the first solder balls 102 a and the second solder ball 102 b, similar to that of the package 10 e of FIG. 1E. In addition and referring to FIG. 1G, the height of each conductive post 130 b is substantially equal to the depth of the corresponding opening 116. In other words, an end (e.g., a lower end) of each conductive post 130 b is aligned (e.g., substantially aligned or coplanar) with the second surface 114 of the dielectric layer 110, and the solder balls 102 are disposed adjacent to their respective conductive posts 130 b, with little or no portions of the solder balls 102 disposed in the openings 116.

FIG. 1H is a cross-sectional view of a package 10 h according to another embodiment of the present invention. Referring to both FIG. 1A and FIG. 1H, the package 10 h of FIG. 1H is similar to the package 10 a of FIG. 1A. At least one difference is that the adhesive layer 109 b of the package 10 h of FIG. 1H is disposed between the chip 104 and a portion of the patterned conductive layer 120 exposed by the patterned solder resist layer 140 b. In addition, the solder balls 102 of the package 10 h include the first solder balls 102 a and the second solder ball 102 b, similar to that of the package 10 e of FIG. 1E. In addition and referring to FIG. 1H, the height of each conductive post 130 b is substantially equal to the depth of the corresponding opening 116. In other words, an end (e.g., a lower end) of each conductive post 130 b is aligned (e.g., substantially aligned or coplanar) with the second surface 114 of the dielectric layer 110, and the solder balls 102 are disposed adjacent to their respective conductive posts 130 b, with little or no portions of the solder balls 102 disposed in the openings 116.

FIG. 2A is a cross-sectional view of a package 20 a according to another embodiment of the present invention. Referring to FIG. 2A, in the present embodiment, the package 20 a includes a package carrier 200 a, a set of solder balls 202, a chip 204, a set of conductive wires 206, and an encapsulant 208. Certain aspects of the package 20 a can be similar to that previously discussed for FIG. 1A through FIG. 1H, and those aspects are not repeated below.

Specifically, the package carrier 200 a includes a dielectric layer 210, a patterned electrically conductive layer 220, a set of electrically conductive posts 230 a, a patterned etching stop layer 240 (or other barrier layer), and a patterned solder resist layer 250 a. The dielectric layer 210 includes a first surface 212 and a second surface 214 faced away from the first surface 212, and defines a set of through holes 216 extending from the first surface 212 to the second surface 214. The patterned conductive layer 220 is disposed adjacent to and above the first surface 212 of the dielectric layer 210 and covers an end of each of the through holes 216. In other words, the patterned conductive layer 220 can be taken as an non-embedded circuit. The conductive posts 230 a are respectively disposed in the through holes 216. In the present embodiment, a height of each of the conductive posts 230 a is less than a depth of the corresponding through hole 216. The patterned etching stop layer 240 is disposed in the through holes 216 and located between the conductive posts 230 a and the patterned conductive layer 220, wherein the conductive posts 230 a can be connected to the patterned conductive layer 220 through the patterned etching stop layer 240 that is formed of, for example, nickel or another electrically conductive material. The patterned solder resist layer 250 a is disposed adjacent to the first surface 212 of the dielectric layer 210 and covers the patterned conductive layer 220, wherein the patterned solder resist layer 250 a exposes a portion of the patterned conductive layer 220. The exposed portion of the patterned conductive layer 220 can be taken as a set of contact pads.

The solder balls 202 are disposed adjacent to the second surface 214 of the dielectric layer 210 and are located adjacent to their respective conductive posts 230 a. In the present embodiment, since the height of each of the conductive posts 230 a is less than the depth of the corresponding through hole 216, a portion (e.g., a top portion) of each of the solder balls 202 is located in the corresponding through hole 216.

The chip 204 is mounted adjacent to the package carrier 200 a and located adjacent to the first surface 212 of the dielectric layer 210. In the present embodiment, the package 20 a further includes an adhesive layer 209 a, wherein the adhesive layer 209 a is disposed between the chip 204 and the patterned solder resist layer 250 a to bond the chip 204 to the package carrier 200 a.

The chip 204 is electrically connected to the portion of the patterned conductive layer 220 exposed by the patterned solder resist layer 250 a through the conductive wires 206. The encapsulant 208 covers the chip 204, the conductive wires 206, and a portion of the package carrier 200 a.

By forming connections to the patterned conductive layer 220 (i.e., the non-embedded circuit) through the conductive posts 230 a, the package 20 a of the present embodiment has the advantages of reduced package size while coping with a particular circuit layout (e.g., the layout of the patterned conductive layer 220), and controlling the cost and complexity of packaging processes.

FIG. 2B is a cross-sectional view of a package 20 b according to another embodiment of the present invention. Referring to both FIG. 2A and FIG. 2B, the package 20 b of FIG. 2B is similar to the package 20 a of FIG. 2A. At least one difference is that an adhesive layer 209 b of the package 20 b of FIG. 2B is disposed between the chip 204 and a portion of the patterned conductive layer 220 exposed by a patterned solder resist layer 250 b of a package carrier 200 b.

FIG. 2C is a cross-sectional view of a package 20 c according to another embodiment of the present invention. Referring to both FIG. 2A and FIG. 2C, the package 20 c of FIG. 2C is similar to the package 20 a of FIG. 2A. At least one difference is that a height of each conductive post 230 b of a package carrier 200 c of FIG. 2C is substantially equal to a depth of the corresponding through hole 216. In other words, an end (e.g., a lower end) of each conductive post 230 b is aligned (e.g., substantially aligned or coplanar) with the second surface 214 of the dielectric layer 210, and the solder balls 202 are disposed adjacent to their respective conductive posts 230 b, with little or no portions of the solder balls 202 disposed in the through holes 216.

FIG. 2D is a cross-sectional view of a package 20 d according to another embodiment of the present invention. Referring to both FIG. 2A and FIG. 2D, the package 20 d of FIG. 2D is similar to the package 20 a of FIG. 2A. At least one difference is that the adhesive layer 209 b of the package 20 d of FIG. 2D is disposed between the chip 204 and a portion of the patterned conductive layer 220 exposed by the patterned solder resist layer 250 b of a package carrier 200 d. In addition, the height of each conductive post 230 b is substantially equal to the depth of the corresponding through hole 216. In other words, an end (e.g., a lower end) of each conductive post 230 b is aligned (e.g., substantially aligned or coplanar) with the second surface 214 of the dielectric layer 210, and the solder balls 202 are disposed adjacent to their respective conductive posts 230 b, with little or no portions of the solder balls 202 disposed in the through holes 216.

In some embodiments, a surface finishing or passivation layer (not shown) can be disposed adjacent to an exposed surface of a patterned conductive layer to facilitate wire-bonding, which surface passivation layer can include nickel/gold, nickel/cadmium/gold, nickel/silver, gold, tin, alloys thereof (e.g., a tin-lead alloy), silver, electroless nickel electroless palladium immersion gold (ENEPIG), or a combination thereof.

Although the chip 104 or 204 in the aforementioned embodiments is electrically connected to the patterned conductive layer 120 or 220 through a wire-bonding technique, the chip 104 or 204 can also be electrically connected to the patterned conductive layer 120 or 220 through a flip-chip bonding technique, such as by having an exposed surface of the patterned conductive layer 120 or 220 located below the chip 104 or 204. In particular, the chip 104 or 204 can be connected to the exposed surface of the patterned conductive layer 120 or 220 through conductive bumps, such as solder bumps, copper pillars, copper stud bumps, or golden stud bumps. Moreover, an underfill material can be disposed between the chip 104 or 204 and a package carrier for encapsulating or wrapping the conductive bumps.

Processes of fabricating package carriers 300, 400, 500 and 600 are illustrated in the following embodiments accompanying FIG. 3A to FIG. 3R, FIG. 4A to FIG. 4Q, FIG. 5A to FIG. 5M, and FIG. 6A to FIG. 6M.

FIG. 3A to FIG. 3R illustrate a process of fabricating the package carrier 300 according to an embodiment of the present invention. Referring to FIG. 3A, in the present embodiment, an initial electrically conductive layer 302 including a first surface 303 a and a second surface 303 b faced away from the first surface 303 a is provided. The initial conductive layer 302 can be a copper foil, or can be formed of another metal, a metal alloy, or other suitable electrically conductive material.

Then, referring to FIG. 3B, a first carrier 306 and a first dry film layer 304 are disposed adjacent to the first surface 303 a of the initial conductive layer 302, wherein the first dry film layer 304 is located between the first carrier 306 and the initial conductive layer 302.

Next, referring to FIG. 3C, an etching stop layer 308 is formed adjacent to the second surface 303 b of the initial conductive layer 302, such as by deposition or lamination. The etching stop layer 308 can be formed of nickel, or can be formed of another metal, a metal alloy, or other suitable electrically conductive material.

Then, referring to FIG. 3D, an electrically conductive layer 312 is formed adjacent to the etching stop layer 308, such as by deposition or lamination. The conductive layer 312 can be formed of copper, or can be formed of another metal, a metal alloy, or other suitable electrically conductive material.

Next, referring to FIG. 3E, the first carrier 306 is removed to expose the first dry film layer 304, and a second carrier 316 and a second dry film layer 314 are disposed adjacent to the conductive layer 312, wherein the second dry film layer 314 is located between the second carrier 316 and the conductive layer 312.

Referring to both FIG. 3E and FIG. 3F, the initial conductive layer 302 is patterned to form a set of electrically conductive posts 302 a. In the present embodiment, patterning the initial conductive layer 302 includes patterning the first dry film layer 304 to form a first patterned dry film layer (not shown), and etching the initial conductive layer 302 to form the conductive posts 302 a, by using the first patterned dry film as an etching mask and exposing the etching stop layer 308. Then, the first patterned dry film layer is removed.

Next, referring to FIG. 3G, a portion of the etching stop layer 308 exposed outside the conductive posts 302 a is removed to expose a portion of the conductive layer 312, and a patterned etching stop layer 308 a is accordingly formed under the conductive posts 302 a.

Then, referring to both FIG. 3H and FIG. 3I, a dielectric layer 318 is laminated over the conductive layer 312 and then compressed onto the conductive layer 312 by a thermal compressing process, wherein the conductive posts 302 a respectively extend through a set of openings 318 a pre-defined in the dielectric layer 318 and are exposed by the dielectric layer 318. The dielectric layer 318 can be, for example, a prepreg.

Next, referring to FIG. 3J, a portion of each of the conductive posts 302 a is removed to form a set of truncated conductive posts 302 b, wherein a sum of a height of one of the conductive posts 302 b and a thickness of the patterned etching stop layer 308 a is less than a thickness of the dielectric layer 318. In the present embodiment, a portion of each of the conductive posts 302 a can be removed by etching or another material removal technique, such that an end of each of the conductive posts 302 b facing away from the conductive layer 312 is concave or has another curved profile.

Then, referring to FIG. 3K, a third d layer 322 is disposed adjacent to the dielectric layer 318.

Next, referring to FIG. 3L, the second carrier 316 adjacent to the second dry film layer 314 is removed, and a third carrier 324 is disposed adjacent to the third dry film layer 322, wherein the third dry film layer 322 is located between the third carrier 324 and the dielectric layer 318.

Then, referring to both FIG. 3L and FIG. 3M, the conductive layer 312 is patterned to form a patterned electrically conductive layer 312 a. In the present embodiment, patterning the conductive layer 312 includes patterning the second dry film layer 314 to form a second patterned dry film layer (not shown), and etching the conductive layer 312 to form the patterned conductive layer 312 a, by using the second patterned dry film as an etching mask and exposing a portion of the dielectric layer 318. Then, the second patterned dry film layer is removed.

Next, referring to FIG. 3N, a patterned solder resist layer 326 is formed adjacent to the dielectric layer 318, wherein the patterned solder resist layer 326 exposes a portion of the patterned conductive layer 312 a.

Then, referring to FIG. 3O, a surface passivation layer 328 is formed adjacent to and covers the portion of the patterned conductive layer 312 a exposed by the patterned solder resist layer 326. It is noted that the surface passivation layer 328 can reduce the oxidation rate of the patterned conductive layer 312 a and can enhance bonding between the patterned conductive layer 312 a and conductive wires (not shown), when the patterned conductive layer 312 a serves as bonding pads for a wire-bonding technique. The surface passivation layer 328 can include nickel/gold, nickel/cadmium/gold, nickel/silver, gold, tin, alloys thereof (e.g., a tin-lead alloy), silver, ENEPIG, or a combination thereof.

Next, referring to FIG. 3P, the third carrier 324 is removed to expose the third dry film layer 322.

Then, referring to FIG. 3Q, the third dry film layer 322 is removed to expose the dielectric layer 318 and the conductive posts 302 b.

After that, referring to FIG. 3R, a surface passivation layer 332 is formed adjacent to the conductive posts 302 b, wherein the surface passivation layer 332 can be an anti-oxidation layer, such as an Organic Solderability Preservative (OSP) to reduce the oxidation rate of the conductive posts 302 b. The OSP can include benzotriazole, benzimidazoles, or combinations and derivatives thereof. In such manner, the package carrier 300 is formed.

The present embodiment forms the conductive posts 302 a that are connected to the conductive layer 312, compresses the dielectric layer 318 onto the conductive layer 312 while exposing a portion of each of the conductive posts 302 a, and then forms the patterned conductive layer 312 a to obtain the package carrier 300 including a non-embedded circuit and the conductive posts 302 b.

Once the package carrier 300 is fabricated, a package according to an embodiment of the invention can be fabricated by disposing a chip (e.g., the chip 204 in FIG. 2A) adjacent to the package carrier 300, electrically connecting the chip to the patterned conductive layer 312 a, and disposing solder balls (e.g., the solder balls 202 of FIG. 2A) adjacent to the conductive posts 302 b. By forming connections to the patterned conductive layer 312 a (i.e., the non-embedded circuit) through the conductive posts 302 b, the resulting package has the advantages of reduced package size while coping with a particular circuit layout (e.g., the layout of the patterned conductive layer 312 a), and controlling the cost and complexity of packaging processes.

FIG. 4A to FIG. 4Q illustrate a process of fabricating the package carrier 400 according to an embodiment of the present invention. Referring to FIG. 4A, in the present embodiment, an initial electrically conductive layer 402 including a first surface 403 a and a second surface 403 b faced away from the first surface 403 a is provided. The initial conductive layer 402 can be a copper foil, or can be formed of another metal, a metal alloy, or other suitable electrically conductive material.

Then, referring to FIG. 4B, a first carrier 406 and a first dry film layer 404 are disposed adjacent to the first surface 403 a of the initial conductive layer 402, wherein the first dry film layer 404 is located between the first carrier 406 and the initial conductive layer 402.

Next, referring to FIG. 4C, an etching stop layer 408 is formed adjacent to the second surface 403 b of the initial conductive layer 402, such as by deposition or lamination. The etching stop layer 408 can be formed of nickel, or can be formed of another metal, a metal alloy, or other suitable electrically conductive material.

Then, referring to FIG. 4D, an electrically conductive layer 412 is formed adjacent to the etching stop layer 408, such as by deposition or lamination. The conductive layer 412 can be formed of copper, or can be formed of another metal, a metal alloy, or other suitable electrically conductive material.

Next, referring to FIG. 4E, the first carrier 406 is removed to expose the first dry film layer 404, and a second carrier 416 and a second dry film layer 414 are disposed adjacent to the conductive layer 412, wherein the second dry film layer 414 is located between the second carrier 416 and the conductive layer 412.

Referring to both FIG. 4E and FIG. 4F, the initial conductive layer 402 is patterned to form a set of electrically conductive posts 402 a. In the present embodiment, patterning the initial conductive layer 402 includes patterning the first dry film layer 404 to form a first patterned dry film layer (not shown), and etching the initial conductive layer 402 to form the conductive posts 402 a, by using the first patterned dry film as an etching mask and exposing the etching stop layer 408. Then, the first patterned dry film layer is removed.

Next, referring to FIG. 4G, a portion of the etching stop layer 408 exposed outside the conductive posts 402 a is removed to expose a portion of the conductive layer 412, and a patterned etching stop layer 408 a is accordingly formed under the conductive posts 402 a.

Then, referring to both FIG. 4H and FIG. 4I, a dielectric layer 418 is laminated over the conductive layer 412 and then compressed onto the conductive layer 412 by a thermal compressing process, wherein the conductive posts 402 a respectively extend through a set of openings 418 a pre-defined in the dielectric layer 418 and are exposed by the dielectric layer 418. The dielectric layer 418 can be, for example, a prepreg. In the present embodiment, a sum of a height of one of the conductive posts 402 a and a thickness of the patterned etching stop layer 408 a is substantially equal to a thickness of the dielectric layer 418. Also, a portion of each of the conductive posts 402 a can be removed by etching or another material removal technique, such that an end of each of the conductive posts 402 a facing away from the conductive layer 412 is concave or has another curved profile.

Then, referring to FIG. 4J, a third dry film layer 422 is disposed adjacent to the dielectric layer 418, wherein an end of each of the conductive posts 402 a directly contacts the third dry film layer 422.

Next, referring to FIG. 4K, the second carrier 416 adjacent to the second dry film layer 414 is removed, and a third carrier 424 is disposed adjacent to the third dry film layer 422, wherein the third dry film layer 422 is located between the third carrier 424 and the dielectric layer 418.

Then, referring to both FIG. 4K and FIG. 4L, the conductive layer 412 is patterned to form a patterned electrically conductive layer 412 a. In the present embodiment, patterning the conductive layer 412 includes patterning the second dry film layer 414 to form a second patterned dry film layer (not shown), and etching the conductive layer 412 to form the patterned conductive layer 412 a, by using the second patterned dry film as an etching mask and exposing a portion of the dielectric layer 418. Then, the second patterned dry film layer is removed.

Next, referring to FIG. 4M, a patterned solder resist layer 426 is formed adjacent to the dielectric layer 418, wherein the patterned solder resist layer 426 exposes a portion of the patterned conductive layer 412 a.

Then, referring to FIG. 4N, a surface passivation layer 428 is formed adjacent to and covers the portion of the patterned conductive layer 412 a exposed by the patterned solder resist layer 426. It is noted that the surface passivation layer 428 can reduce the oxidation rate of the patterned conductive layer 412 a and can enhance bonding between the patterned conductive layer 412 a and conductive wires (not shown), when the patterned conductive layer 412 a serves as bonding pads for a wire-bonding technique. The surface passivation layer 428 can include nickel/gold, nickel/cadmium/gold, nickel/silver, gold, tin, alloys thereof (e.g., a tin-lead alloy), silver, ENEPIG, or a combination thereof.

Next, referring to FIG. 4O, the third carrier 424 is removed to expose the third dry film layer 422.

Then, referring to FIG. 4P, the third dry film layer 422 is removed to expose the dielectric layer 418 and the conductive posts 402 a.

After that, referring to FIG. 4Q, a surface passivation layer 432 is formed adjacent to the conductive posts 402 a, wherein the surface passivation layer 432 can be an anti-oxidation layer, such as an OSP to reduce the oxidation rate of the conductive posts 402 a. In such manner, the package carrier 400 is formed.

Once the package carrier 400 is fabricated, a package according to an embodiment of the invention can be fabricated by disposing a chip (e.g., the chip 204 in FIG. 2C) adjacent to the package carrier 400, electrically connecting the chip to the patterned conductive layer 412 a, and disposing solder balls (e.g., the solder balls 202 of FIG. 2C) adjacent to the conductive posts 402 a.

FIG. 5A to FIG. 5M illustrate a process of fabricating the package carrier 500 according to an embodiment of the present invention. Referring to FIG. 5A, in the present embodiment, an initial electrically conductive layer 502 including a first surface 503 a and a second surface 503 b faced away from the first surface 503 a is provided. The initial conductive layer 502 can be a copper foil, or can be formed of another metal, a metal alloy, or other suitable electrically conductive material.

Next, referring to FIG. 5B, a first carrier 504 is disposed adjacent to the second surface 503 b of the initial conductive layer 502.

Then, referring to FIG. 5C, a patterned electrically conductive layer 506 is formed adjacent to the first surface 503 a of the initial conductive layer 502 by a semi-additive process. Specifically, a dielectric material, a photo-resist, or another applicable material serving as a temporary mask is disposed adjacent to the initial conductive layer 502. Then, the mask is patterned to form a set of openings at locations corresponding to the patterned conductive layer 506. The patterned conductive layer 506 is then formed in the openings in a plating process, by using the initial conductive layer 502 as an electrode (e.g., a cathode). After that, the mask for plating is removed.

Then, referring to FIG. 5D, a set of electrically conductive posts 508 are formed adjacent to the patterned conductive layer 506 by a semi-additive process. Specifically, a dielectric material, a photo-resist, or another applicable material serving as a temporary mask is disposed adjacent to the structure of FIG. 5C. Then, the mask is patterned to form a set of openings at locations corresponding to the conductive posts 508. The conductive posts 508 are then formed in the openings in a plating process, by using the initial conductive layer 502 and the patterned conductive layer 506 as an electrode (e.g., a cathode). After that, the mask for plating is removed.

Then, referring to both FIG. 5E and FIG. 5F, a dielectric layer 512 is laminated over the first surface 503 a of the initial conductive layer 502 and then compressed onto the first surface 503 a of the initial conductive layer 502 by a thermal compressing process, wherein the conductive posts 508 respectively extend through a set of openings 512 a pre-defined in the dielectric layer 512 and are exposed by the dielectric layer 512. The dielectric layer 512 can be, for example, a prepreg.

Next, referring to FIG. 5G, a portion of each of the conductive posts 508 is removed to form a set of truncated conductive posts 508 a, wherein a sum of a height of one of the conductive posts 508 a and a thickness of the patterned conductive layer 506 is less than a thickness of the dielectric layer 512. In the present embodiment, a portion of each of the conductive posts 508 can be removed by etching or another material removal technique, such that an end of each of the conductive posts 508 a facing away from the patterned conductive layer 506 is concave or has another curved profile.

Next, referring to FIG. 5H, the first carrier 504 is removed to expose the second surface 503 b of the initial conductive layer 502, and a second carrier 516 and a dry film layer 514 are disposed adjacent to the dielectric layer 512, wherein the dry film layer 514 is located between the second carrier 516 and the dielectric layer 512.

Then, referring to FIG. 5I, the initial conductive layer 502 is removed to expose the dielectric layer 512 and the patterned conductive layer 506. The initial conductive layer 502 can be removed by etching or another material removal technique.

Next, referring to FIG. 5J, a patterned solder resist layer 518 is formed adjacent to the dielectric layer 512, wherein the patterned solder resist layer 518 exposes a portion of the patterned conductive layer 506.

Afterwards, referring to FIG. 5K, a surface passivation layer 522 is formed adjacent to and covers the portion of the patterned conductive layer 506 exposed by the patterned solder resist layer 518. It is noted that the surface passivation layer 522 can reduce the oxidation rate of the patterned conductive layer 506 and can enhance bonding between the patterned conductive layer 506 and conductive wires (not shown), when the patterned conductive layer 506 serves as bonding pads for a wire-bonding technique.

Then, referring to FIG. 5L, the second carrier 516 and the dry film layer 514 are removed to expose the dielectric layer 512 and the conductive posts 508 a.

After that, referring to FIG. 5M, a surface passivation layer 524 is formed adjacent to the conductive posts 508 a, wherein the surface passivation layer 524 can be an anti-oxidation layer, such as an OSP to reduce the oxidation rate of the conductive posts 508 a. In such manner, the package carrier 500 is formed.

The present embodiment forms the conductive posts 508 that are connected to the patterned conductive layer 506, compresses the dielectric layer 512 onto the patterned conductive layer 506 while exposing a portion of each of the conductive posts 508, thereby obtaining the package carrier 500 including an embedded circuit and the conductive posts 508 a.

Once the package carrier 500 is fabricated, a package according to an embodiment of the invention can be fabricated by disposing a chip (e.g., the chip 104 in FIG. 1A) adjacent to the package carrier 500, electrically connecting the chip to the patterned conductive layer 506, and disposing solder balls (e.g., the solder balls 102 of FIG. 1A) adjacent to the conductive posts 508 a. By forming connections to the patterned conductive layer 506 (i.e., the embedded circuit) through the conductive posts 508 a, the resulting package has the advantages of reduced package size while coping with a particular circuit layout (e.g., the layout of the patterned conductive layer 506), and controlling the cost and complexity of packaging processes.

FIG. 6A to FIG. 6M illustrate a process of fabricating the package carrier 600 according to an embodiment of the present invention. Referring to FIG. 6A, in the present embodiment, an initial electrically conductive layer 602 including a first surface 603 a and a second surface 603 b faced away from the first surface 603 a is provided. The initial conductive layer 602 can be a copper foil, or can be formed of another metal, a metal alloy, or other suitable electrically conductive material.

Next, referring to FIG. 6B, a first carrier 604 is disposed adjacent to the second surface 603 b of the initial conductive layer 602.

Next, referring to FIG. 6C, a patterned electrically conductive layer 606 is formed adjacent to the first surface 603 a of the initial conductive layer 602 by a semi-additive process, similar to that discussed above for FIG. 5C.

Then, referring to FIG. 6D, a set of electrically conductive posts 608 are formed adjacent to the patterned conductive layer 606 by a semi-additive process, similar to that discussed above for FIG. 5D.

Then, referring to both FIG. 6E and FIG. 6F, a dielectric layer 612 is laminated over the first surface 603 a of the initial conductive layer 602 and then compressed onto the first surface 603 a of the initial conductive layer 602 by a thermal compressing process, wherein the conductive posts 608 respectively extend through a set of openings 612 a pre-defined in the dielectric layer 612 and are exposed by the dielectric layer 612. The dielectric layer 612 can be, for example, a prepreg.

Next, referring to FIG. 6G, a portion of each of the conductive posts 608 is removed to form a set of truncated conductive posts 608 a, wherein a sum of a height of one of the conductive posts 608 a and a thickness of the patterned conductive layer 606 is substantially equal to a thickness of the dielectric layer 612. In the present embodiment, a portion of each of the conductive posts 608 can be removed by etching or another material removal technique, such that an end of each of the conductive posts 608 a facing away from the patterned conductive layer 606 is concave or has another curved profile.

Next, referring to FIG. 6H, the first carrier 604 is removed to expose the second surface 603 b of the initial conductive layer 602, and a second carrier 616 and a dry film layer 614 are disposed adjacent to the dielectric layer 612, wherein the dry film layer 614 is located between the second carrier 616 and the dielectric layer 612.

Then, referring to FIG. 6I, the initial conductive layer 602 is removed to expose the dielectric layer 612 and the patterned conductive layer 606. The initial conductive layer 602 can be removed by etching or another material removal technique.

Next, referring to FIG. 6J, a patterned solder resist layer 618 is formed adjacent to the dielectric layer 612, wherein the patterned solder resist layer 618 exposes a portion of the patterned conductive layer 606.

Afterwards, referring to FIG. 6K, a surface passivation layer 622 is formed adjacent to and covers the portion of the patterned conductive layer 606 exposed by the patterned solder resist layer 618. It is noted that the surface passivation layer 622 can reduce the oxidation rate of the patterned conductive layer 606 and can enhance bonding between the patterned conductive layer 606 and conductive wires (not shown), when the patterned conductive layer 606 serves as bonding pads for a wire-bonding technique.

Then, referring to FIG. 6L, the second carrier 616 and the dry film layer 614 are removed to expose the dielectric layer 612 and the conductive posts 608 a.

After that, referring to FIG. 6M, a surface passivation layer 624 is formed adjacent to the conductive posts 608 a, wherein the surface passivation layer 624 can be an anti-oxidation layer, such as an OSP to reduce the oxidation rate of the conductive posts 608 a. In such manner, the package carrier 600 is formed.

Once the package carrier 600 is fabricated, a package according to an embodiment of the invention can be fabricated by disposing a chip (e.g., the chip 104 in FIG. 1C) adjacent to the package carrier 600, electrically connecting the chip to the patterned conductive layer 606, and disposing solder balls (e.g., the solder balls 102 of FIG. 1C) adjacent to the conductive posts 608 a.

It should be recognized that similar operations as discussed for FIG. 3A to FIG. 3R, FIG. 4A to FIG. 4Q, FIG. 5A to FIG. 5M, and FIG. 6A to FIG. 6M can be used to fabricate other package carriers and packages (e.g., as illustrated in FIG. 1B, FIG. 1D to FIG. 1H, FIG. 2B, and FIG. 2D).

In summary, in a package carrier of some embodiments of the invention, electrically conductive posts can be used so as to effectively reduce a package size and a package area, while controlling the cost and complexity of packaging processes.

While the invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, modifications may be made to adapt a particular situation, material, composition of matter, method, or process, within the scope of the claims, including variances or tolerances attributable to manufacturing processes and techniques. In particular, while the methods disclosed herein have been described with reference to particular operations performed in a particular order, it will be understood that these operations may be combined, sub-divided, or re-ordered to form an equivalent method and resultant structure consistent with the teachings of the invention. 

What is claimed is:
 1. A semiconductor package, comprising: a package carrier including: a dielectric layer defining a plurality of through holes extending from a top surface of the dielectric layer to a bottom surface of the dielectric layer, wherein a first of the plurality of through holes has a first lateral extent larger than a second lateral extent of a second of the plurality of through holes; a conductive pillar disposed within the first through hole defined by the dielectric layer; and a conductive layer extending over a portion of the dielectric layer surrounding the first through hole defined by the dielectric layer, the conductive layer further defining a pad adjacent to the dielectric layer; and a chip attached to the package carrier, wherein an active surface of the chip is electrically connected to the pad.
 2. The semiconductor package of claim 1, wherein a bottom end of the conductive pillar is concave.
 3. The semiconductor package of claim 1, wherein a lower surface of the conductive pillar is recessed from the bottom surface of the dielectric layer.
 4. The semiconductor package of claim 1, wherein the conductive pillar is configured to relieve mechanical stress to the package.
 5. The semiconductor package of claim 1, further comprising a barrier layer disposed at least partially within the first through hole defined by the dielectric layer, the barrier layer being adjacent to the conductive pillar.
 6. The semiconductor package of claim 1, wherein a top surface of the conductive pillar is recessed below the top surface of the dielectric layer. 